International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B2. Istanbul 2004
are images with evident texture of classes, designed with use of
Brodatz textures (Figure 2).
Figure 2. Model image with evident textures of classes
4.2 Nonparametric density estimation
The efficiency investigation of density estimation algorithms is
performed for the determination of the computational cost
(Figure 3 a)) and the accuracy (Figure 3 b)) of classification, on
the example of seven bands image of type as shown in Figure 1.
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Figure 3. Computational cost and accuracy of classification
algorithms used
In Figure 3 the following symbols are defined: 1 — using of
traditional maximum likelihood classification, 2 — using of
ordinary RP algorithm based upon (2), 3 — using ol ordinary k-
NN algorithm based upon (3) and (4), 4 — using the proposed
original statistical nonparametric algorithm.
Figure 3 a) shows the original algorithm provides
computational performance increase in dozens times compared
to traditional nonparametric density estimation algorithms. At
that the performance of original algorithm is increasing together
with the increasing of sample size.
At the same time Figure 3 b) shows the accuracy of the
proposed algorithm is almost the same as the accuracy of
traditional nonparametric algorithms, and also it should be
noted the accuracy with use of parametric algorithm of density
estimation is inappropriate low. It proofs necessity of
developing nonparametric algorithms that are invariant to the
distribution in a sample.
4.3 Classification with spatial features
The important element of the advanced interpretation is the
classification of RS images with use of texture features of the
classes that is needed for high accuracy interpretation. In the
framework of the developing approach it is proposed to define
prior probabilities of classes by either statistical or ANN ways
and each way takes into account the spatial features of classes.
The efficiency investigation of some algorithms with use of
different types of model images is conducted. The purpose of
the research is to define how the proposed ways of forming
spatial feature space consider texture information about classes.
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Figure 4. The classification accuracy of statistical and ANN
algorithms with different types of model images
used
The Figure 4 shows the investigation results of accuracy
classification for different ways of forming feature space.
In Figure 4 the following symbols are defined: 1 — traditional
maximum likelihood classification, 2 — ordinary RP algorithm
based upon (2), 3 — ordinary k-NN algorithm based upon (3)
and (4) 4 — the proposed ANN original algorithm using
context-spectral way of forming feature space, 5 — the proposed
nonparametric algorithm using Haralick texture characteristics
(Haralick R.M. & Joo H. A, 1986). The following types of
model images on the abscissa axis are scaled: typela and
typelb — the first type model images (Figure 1) with three and
seven bands consequently; type2a and type2b — the second type
model images (Figure 2) with only one and six bands
consequently.
Figure 4 presents the property to get more accurate results of
the ANN classification with context-spectral forming feature
space due to considering texture features in multispectral
images. The noticeable effect of that in case of ANN
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